Create aliases for built in functions

[FezVrasta]

I mean, if I use multiple times Math.floor, it would make sense to assign it to a variable and use the variable.

function(x, y,z) {
  return { Math.floor(x), Math.floor(y), Math.floor(z)  };
}

To

function(x, y, z) {
  let a = Math.floor;
  return { a(x), a(y), a(z) };
}

[kangax]

We can do that if we know that a function call is idempotent (i.e. has no side effects). In this case, Math.floor is a getter but if this was doSomethingDestructive(x) + doSomethingDestructive(y) then we go from a side effect that happens twice to a side effect that happens once, which changes behavior.

We can maintain our own list of pure functions and/or allow for specifying a whitelist via options.

[FezVrasta]

Why you say so? You would alias the function before it's executed.

so:

let a = doSomethingDestructive;
a(x) + a(y)

The result would be the same.

[kangax]

Oh, you're right. I was thinking of getters (when foo.bar evaluation has a side effect). This should be safer to implement then, as long as safeGetters option is enabled.

[vigneshshanmugam]

Gonna try it out. @kangax @boopathi